THE 


ANATOMY  AND  PHYSIOLOGY  OF  EXPRESSION, 

% 

V  A.ND  THE 


HUMAN  TEETH 


IN  THEIR 

/■ 

RELATIONS  TO  MASTICATION,  SPEECH,  AND  APPEARANCE 


BY 

J.  H.  McQUILLEJSr,  D.  D.  S., 

•b- 

PROFESSOR  OF  ANATOMY,  PHYSIOLOGY,  AND  HYGIENE  IN  THE  PHILADELPHIA  DENTAL  COLLEGE. 


PHILADELPHIA: 

J.  B.  LIPPINCOTT  &  CO. 
1864. 


Ulf-/  - 


-  >V  ’  - 


i‘  •. 


» '’V  , 


■  ■••^  .■ 


t^.-. 


'  ^  .'■  'j--.  .  ,  ‘'4 , '-■'1.'' ;  -'sf', 

. ’  ; '■  \r'0^i 

^  -  mMmn  uo  ^obisiaYHi r/<mM 


JUT,.;.  "■  m 


•  M'  .',  •  •  •'■'  N  •  >V\ . 


•■> 

'.i 


\.' 


y  V, 

>'  •• . 
.y 


’i 


■  ^ 


V^-'v., 


aiarc'^  s:i 


V :  ^ 


-  y  Vi 

■  .il  .“f  ' 

» 

,,.>  ■; ;:  '^A' ;v 

,•  -,  tlf  *’  -Ml 

■  •  _ 'N  ;'  Vc-'l 

/  . , 

'r.  - 

:;;  ■\' 

■  AH 

1 

.  . 

■v-N 

If  ■' 

,  A  '  ■  '  ■  'Pn 

*' , 

'  *1 

^  ' 

>  .  K':i 

.  U^h^'i'lL  (}. A  'j h. . /1 01T.A'Ji;i cjipi  OT 


V*.  *  *  •  . 

■  -V 1*  r.'  ’>  •■ 


s  .•.■**•*' 

•"'  'v:: 


'  ^ 

■>■■•'.’  I.' 


J  '  'y*  *  *'■.  ’■y  'r  ''^.  < 

'  -r  ■»  .  ■  ".'  -'  y  h  ■.  •- 

■  1  '  •■>  i  .  ■ 


m 


WT- 


V-’  '*t 


•  *  *  *'  •  *  »' 


<  f 


'.-  ■  •*  •’. j-V?. 


•  %■.•;•  ■  I  •  ■• 


a 


y- 


f  ,  ■  -4-  ‘ 

'  .  V  V. .  -V  ► ' 


vv 


:.  ♦  i 

* 


.  '  V  ii. 


ra 

■■-.Y ' 


■yy 


’ :  ^^V^l 

%.8:a:a'  ,>i;-LaJ:'!'tJ^:yM  .-.r. 


,  'V 


V..;;.  ._  -.  v,,->  ■ 

■  -  ■ /.v' ■  :*  '  ■  ■•  ■  '  ,, 


.  '4.  ■ 


:v.. 


V 

■ '  > 


■  —+■'4' V 


"i 

-■  'T  ,  V  V'.v 


•  •  V'  •  ?  N  - 


. :  ? 


,‘;^  t' 

.  »■% 


.  • : 


t  ,  /;:.  ■'  _  •  .-  '  ;.,  .m."  .  ^  •:: 

■  •  '•  ^r'.:.:  '  '  '  ■  ■■■■ 


•  r.r*  i 


^LA  }i^'>.'  A  ,  • 

.  '  ♦ 


,  .^ -.  *  •  .  '•  '  •' V,  ’•  .  :  .  ,  /  X  •...*..  ^^ 


.  y^  ' 

'/■  "r  ' 


■  A 


.■L\l  ' 


:  •  *.  r 


.  r  , 


..V  >  V'-r  , 

'  )■  rtl  J>*  • 


'  ■  .  '< 

• ,  r  ^  '  ■  .. 

V  ■  •  .  •.  t 


i  •  • 

^  V 


■  '*  i 

"•  w 


\  * 


m 

■T.  <■ 


' •■•  I  •  /  *i. 


J 


PREFACE. 


The  accompanying  Addresses  may  be  said  to  have  had  their  origin 
in  a  communication  published  by  me  in  the  Dental  Cosmos,  in  connec¬ 
tion  with  an  extract  from  an  article  by  Prof.  Oliver  Wendell  Holmes,  on 
‘*The  Doings  of  the  Sunbeam,”  presented  in  the  Atlantic  Monthly. 
My  remarks  were  as  follows : — 

“  When  it  is  remembered  that  within  the  few  square  inches  comprised 
by  the  human  face,  room  is  found  not  only  for  traits  of  all  of  one’s  ances¬ 
tors,  but  also  that  the  cares  and  anxieties,  the'joys  and  sorrows,  the  hopes 
and  fears,  and  the  moral,  mental,  and  social  associations  and  trainings  of 
the  past  of  a  person,  leave  ineffacable  traces,  which  are  perceptible  to  the 
most  obtuse,  if  they  will  exercise  their  perceptive  faculties,  and  which 
enable  the  keen  and  philosophical  observer  to  form  a  fair  estimate  of  the 
past  experience  and  present  and  future  capabilities  of  the  individual,  it  is 
not  a  matter  of  surprise  that  Lavater,  and  others,  who  have  made  the 
human  face  a  special  object  of  study,  should  have  been  so  enthusiastic 
with  regard  to  it.  Moore,  it  is  true,  has  said — 

^“In  vain  we  dwell  on  lines  and  crosses, 

Crooked  mouths,  or  short  proboscis: 

Boobies  have  looked  as  wise  and  bright 
As  Plato,  or  the  Stagyrite; 

And  many  a  sage  and  learned  skull 

Has  peeped  through  windows  dark  and  dull.’ 

While  this  is  undoubtedly  true  in  exceptional  cases,  there  is  more  of 
poetic  imagination  than  actual  truth  in  a  broad  application  of  such  as¬ 
sertions  ;  for  there  is  almost  invariably  associated  with  high  moral  and 
mental  manifestations,  or  the  reverse,  an  unmistakable  evidence  of  the 
fact  on  the  brow  of  the  person.  It  may  not  be  evident  at  a  first  and 
superficial  glance,  or  when  the  features  are  in  repose ;  but  the  spirit 

2  (iii) 


4 


which  brings  the  muscles  of  expression  into  action  speaks  through  them 
in  a  language  not  easy  to  be  mistaken. 

“All  persons,  from  the  lisping  babe  to  the  hoary  patriarch,  are  more  or 
less  physiognomists ;  in  other  words,  are  attracted  or  repelled  by  the 
expressions  of  the  face.  With  the  many,  the  impressions  formed  are  in¬ 
stinctive  and  emotional  in  their  character,  rather  than  the  results  of  calm 
and  philosophical  reasoning.  The  opinions  arrived  at  under  the  former 
conditions  of  mind,  as  a  general  thing,  are  not  very  reliable,  and  are 
apt  to  be  abandoned  as  quickly  as  they  were  adopted,  and  are  quite  as 
unimportant  in  their  results  as  hasty  conceptions  generally  are;  but 
those  whose  duties  bring  them  in  contact  with  large  numbers  of  their 
fellow-beings  must,  of  necessity,  depend  in  a  great  measure  on  the  phy¬ 
siognomy  for  an  estimate  of  the  character  and  capacities  of  those  who 
come  before  them  as  strangers  for  a  brief  period  only ;  and  while  it  would 
not  do  to  rely  implicitly  and  irrevocably  on  such  data,  a  person  of  large 
experience,  possessed  of  fair  perceptive  and  reasoning  faculties,  is  not 
likely  to  be  led  far  astray  in  his  conclusions. 

“  It  is  not  merely  as  a  means  of  forming  an  estimate  of  character  that 
the  face  becomes  an  interesting  and  important  object  of  study.  To  the 
artist,  whether  as  a  sculptor  or  a  painter,  who  aims  to  excel  as  a  deli¬ 
neator  of  nature,  it  recommends  itself  with  peculiar  force.  Every  one’s 
attention  is  liable  to  be  attracted  by  strongly-marked  and  characteristic 
features.  A  high  and  expanded  forehead,  a  prominent  nose,  and  dark 
and  expressive  eye,  or  a  mouth  indicating  firmness  of  purpose,  are  not 
likely  to  escape  observation  and  comment ;  but  to  perceive  and  retain  in 
the  memory  those  fine  shades  of  difference  which  exist  between  the  mass 
of  faces,  (that  are  so  much  alike,  and  yet  so  dissimilar,)  and  delineate  them 
in  marble  or  on  canvas  so  perfectly  that  there  can  be  no  question  as  to 
the  resemblance,  requires  peculiar  natural  gifts,  combined  with  long-con¬ 
tinued  and  careful  study  of  the  face  during  life,  when  by  the  action  of 
the  muscles  of  expression  it  is  constantly  undergoing  a  thousand  and 
one  changes,  and  by  frequent  dissections  of  the  cadaver  to  ascertain  the 
size,  shape,  origin,  and  insertion,  and  the  relations  which  these  muscles 
bear  to  one  another  and  the  surrounding  parts. 

“  To  no  one,  however,  does  the  study  of  the  human  face,  in  its  various 
forms  and  aspects,  recommend  itself  with  more  force  than  to  the  dental 


5 


practitioner;  for,  called  upon  as  he  is,  not  only  to  relieve  suffering  hu¬ 
manity  from  the  greatest  pain  to  which  flesh  is  heir,  but  also  to  repair  the 
ravages  of  decay,  either  in  efforts  directed  toward  the  preservation  of  the 
natural  organs,  or,  when  these  are  lost,  to  supply  artificial  substitutes,  if 
he  is  not  as  quick  to  perceive  and  as  able  to  retain  in  his  memory  the 
nice  shades  of  expression  of  the  same  face,  and  the  characteristic  points 
of  resemblance  or  difference  between  various  individuals  as  the  sculptor 
or  painter,  he  will  fail  in  many  essential  particulars  to  meet  all  the  just 
and  proper  demands  upon  him. 

'‘A  practitioner  always  on  the  watch,  and  quick  to  perceive  the  slight¬ 
est  change  of  expression  in  the  face  of  his  patients  when  operating  in  the 
neighborhood  of  an  exposed  pulp,  or  in  administering  an  anaesthetic,  will 
be  much  less  likely  to  give  unnecessary  pain,  or  bring  life  in  jeopardy, 
than  those  who  are  indifferent  in  regard  to  such  matters.  Again,  it  is 
not  reasonable  to  suppose  that  a  symmetrical  and  natural  appearance  can 
be  given  to  teeth  much  broken  up  by  decay,  when  the  effort  to  file  or  fill 
them  is  intrusted  to  one  who  has  not  paid  due  attention  to  the  form, 
position,  and  relations  of  the  dental  organs  in  their  normal  condition ;  or 
that  such  a  one  can  arrange  and  insert  artificial  substitutes  with  any 
certainty  that  they  will  preserve  or  restore  the  old  and  familiar  expres¬ 
sions  of  the  face,  so  well  remembered  and  possibly  admired  by  friends  and 
acquaintances.  Opportunities,  indeed,  are  sometimes  offered,  requiring 
little  or  no  effort  to  improve  the  appearance  by  the  introduction  of  arti¬ 
ficial  teeth;  but  to  accurately  meet  the  varied  complexions  and  forms  of 
face  which  present  themselves,  so  that  the  results  shall  prove  faultless  in 
their  adaptation,  is  deserving  of  the  highest  meed  of  gratitude  and  praise 
on  the  part  of  the  patients. 

“As  the  most  careful  observers  and  the  best  judges  of  what  constitutes 
a  natural  expression,  can  only  form  an  approximate  estimate  of  the  ex¬ 
pression  of  those  whom  they  are  called  on  to  serve  after  the  loss  of  natu¬ 
ral  teeth,  it  is  reasonable  to  infer  that  valuable  assistance  would  be  found 
by  bringing  in  the  aid  of  photography  to  determine  nice  or  doubtful 
points  under  such  circumstances.  Indeed,  as  the  memory  of  man  is  so 
treacherous,  it  would  be  of  assistance  even  in  cases  where  the  face  is  long 
and  well  known  to  the  operator.  At  a  period  when  photographs  are  so 
much  in  vogue  that  they  are  used  as  ^'cartes  de  visile, and  when  it  is  the 


6 


exception  where  persons  have  not  sat  for  their  picture,  the  dentist  will 
have  little  or  no  difficulty  in  securing  full-face,  quarter-face,  and  profile 
views  of  patients  taken  long  before  the  loss  of  the' teeth.  With  these  in 
hand,  the  skillful  and  artistic  practitioner  will  be  able  to  preserve  or  re¬ 
store,  or  if  need  be  improve,  the  old  and  familiar  expressions.’’ 

In  connection  with  this,  by  permission  of  the  author,  the  following 
note  is  presented ; — 

“Boston,  Septemher  28,  1863. 

% 

“Dear  Sir:  Many  thanks  for  the  two  numbers  of  the  Dental  Cos¬ 
mos,  and  for  the  compliment  paid  an  article  of  mine  by  taking  it  as  the 
text  of  your  interesting  remarks.  The  subject  is  one  of  great  interest, 
and  will,  I  hope,  receive  a  fuller  development  at  your  hands  hereafter. 

“  I  am,  dear  Sir, 

“Yours  very  truly, 

“O.  W.  HOLMES.” 

In  giving  the  subject  a  “fuller  development,”  my  aim  has  been  to 
treat  it  in  a  suggestive  manner,  so  that  a  spirit  of  inquiry  might  be 
awakened  in  a  direction  not  only  attractive  and  instructive  in  its  nature, 
but  also  capable,  if  the  information  gained  is  rightly  applied,  of  being 
made  subservient  to  the  comfort  and  happiness  of  others. 

Within  the  limits  of  two  brief  addresses  it  was  of  course  impossible  to  ^ 
enter  upon  the  minute  description  of  structure,  or  to  make  that  extended 
practical  application  of  which  the  subject  is  susceptible.  This  can  only 
be  done  in  a  regular  and  systematic  course  of  lectures.  Recognizing  the 
importance  of  such  a  course,  it  has  ever  been  my  practice,  as  a  public 
teacher,  to  present  these  and  analogous  subjects  to  the  attention  of  stu¬ 
dents  in  the  broadest,  most  extended,  and  practical  manner  possible,  in 
my  winter  course  of  lectures  on  Anatomy,  Physiology,  and  Hygiene. 

J.  H.  McQ. 

1112  Arch  Street,  Philadelphia, 

July,  1864. 


ANATOMY  AND  PHYSIOLOGY  OF  EXPRESSION. 

An  Address  delivered  before  the  Odontographic  Society. 


Gentlemen: — As  the  essayist  of  the  evening,  having  no  paper  ready 
to  present,  my  remarks  of  necessity  will  be  of  an  oral  character.  The 
subject  I  have  selected  for  your  consideration  is  one  which  should, 
and  more  or  less  actually  does,  interest  everybody;  for  although  on 
the  part  of  the  many  there  may  not  be  a  recognition  of  the  fact, 
every  one  is  somewhat  of  a  physiognomist;  or,  in  other  words,  intu¬ 
itively  seeks  within  the  few  square  inches  of  the  “human  face  divine,’^ 
to  discover  the  mental  and  social  qualities  and  past  experiences  of 
those  with  whom  he  is  brought  in  contact,  by  the  relations  of  busi¬ 
ness  or  pleasure.  And  there  the  indelible  record  is  made  of  the  mental 
training,  the  high  and  ennobling,  or  the  low  and  degrading  association, 
and  the  joys  and  sorrows  each  individual  being  has  experienced.  Erro¬ 
neous  estimates  may  be,  and  frequently  are  made  by  the  most  acute  ob¬ 
server,  but  this  is  no  evidence  that  the  most  legible  and  unmistakable 
record  was  not  presented  in  each  instance.  An  opinion  of  any  value  is 
not  to  be  formed  by  carelessly  and  indifferently  observing  the  features  when 
in  repose,  or  noting  a  few  changing  expressions  ;  but  by  a  careful  and 
philosophical  examination  under  all  their  varying  and  chamelion-like 
forms.  A  false  estimate  of  character  may  sometimes  be  due  to  the  fact 
that  the  opportunities  and  circumstances  attending  the  examination  have 
not  been  of  such  a  nature  as  to  disclose  all  the  face  was  capable  of  re¬ 
vealing  ;  for  as  a  single  word  often  gives  a  clear  insight  of  the  life  and 
animus  of  an  individual,  so  a  single  look,  indicative  of  love  or  hate, 
hope  or  despair,  will  reveal  traits  of  character  which  the  individual  fully 
recognizes  the  possession  of,  and  studiously  endeavors  to  conceal  from  the 
observation  of  the  world. 

Aside  from  this  general  interest  shared  by  all  in  the  human  face,  it  is 
important  that  those  engaged  in  certain  departments  of  life  should  be¬ 
come  thoroughly  acquainted  with  the  mechanism,  so  to  speak,  by  which 
the  record  is  made.  To  the  speaker,  whether  in  the  pulpit,  at  the  bar, 
or  on  the  stage,  gesture  is  all-important;  to  the  artist,  whether  as  a 

O) 


8 


painter  or  sculptor,  expression  is  everything;  and  last,  though  not  least, 
to  the  dentist  a  faithful  discharge  of  duty  demands  that  he  should,  in 
the  performance  of  his  operations  on  the  teeth,  invariably  endeavor  to 
preserve  the  natural  expression  of  the  face,  or  when  the  ravages  of  de¬ 
cay  have  eventuated  in  the  loss  of  the  dental  organs,  that  the  lost  expres¬ 
sion  should  be  restored  by  the  introduction  of  properly  constructed  and 
adapted  artificial  substitutes.  To  each  and  all  of  these,  and  particularly 
to  the  latter,  if  they  desire  to  attain  the  highest  possible  point  of  excel¬ 
lence,  an  intimate  acquaintance  with  the  anatomy  and  physiology  of  ex¬ 
pression  is  indispensable.  In  the  brief  space  allotted  to  me  this  evening, 
little  more  can  be  done  than  to  offer,  in  a  general  manner,  the  ground¬ 
work  on  which  such  an  interesting  and  extended  study  rests.  It  would 
require  many  evenings,' and  fill  a  large  sized  volume,  to  do  full  justice 
to  the  theme.  With  this  understanding,  permit  me  in  the  first  place  to 
direct  your  attention  to  the  main  characteristics  of  the  bony  framework  ^ 
on  which  the  features  rest,  for  in  the  language  of  Tennyson,— 

“Every  face,  however  full, 

Padded  round  with  flesh  and  fat, 

Is  but  modeled  on  a  skull.” 

The  roundness  and  fullness  of  some  faces,  the  sharp  and  pinched  ap¬ 
pearance,  or  the. long  and  heavy  expression  of  others,  is  mainly  due  to 
the  shape  and  size  of  the  bones  on  which  the  features  are  moulded.  In 
illustration  of  this,  yon  see  on  the  table  a  number  of  cranim,  ranging 
from  the  earliest  period  of  infancy  to  childhood,  adolescence,  manhood, 
and  extreme  old  age ;  and  in  addition,  others  belonging  to  different  races, 
each  and  all  indicating,  in  a  marked  degree,  the  characteristic  differences 
just  referred  to.  In  this,  for  instance,  the  skull  of  an  infant  a  month  or 
so  after  birth,  all  that  portion  which  contained  the  brain  is  relatively 
large,  with  a  full  forehead,  but  rather  flat  at  the  eyebrows,  while  the 
bones  of  the  face  are  diminutive,  and  their  external  surface  smooth  and 
rounded ;  no  great  prominences  and  depressions,  with  the  exception 
of  the  orbital  cavities,  are  presented,  and  everything  contributes  to 
give  the  plump  and  meaningless  expression  characteristic  of  an  in¬ 
fantile  face  while  in  repose.  Passing  to  another  skull  belonging  to 
a  child  set.  six,  the  bones  of  the  face  are  found  largely  increased  in 
size,  and  this,  along  with  the  presence  of  the  deciduous  teeth,  serves  to 
lengthen  the  face,  and  make  it  less  round  than  that  of  the  infant.  The 
gradual  but  marked  increase  of  size  in  the  superior  maxillae  presented 
in  these  skulls,  as  we  pass  from  infancy  to  childhood,  from  childhood  to 
adolescence,  and  from  adolescence  to  manhood,  is  accompanied  by  a  pro- 
ortionate  enlargement  of  the  Antrum  Highmorianum ;  at  the  same 


9 


time,  as  the  centre  bones  of  the  face,  their  growth  has  the  effect  of  in¬ 
creasing  the  length  and  prominence  of  the  nasal  and  malar,  or  cheek 
bones.  ^  The  presence  of  the  large  permanent  teeth  of  the  adult,  and  the 
alveolar  processes  which  support  and  fix  them,  serve  also  to  increase  the 
length,  breadth,  and  depth  of  the  superior  and  inferior  maxillae;  and  the 
entire  face  consequently  becomes  larger  and  longer,  but  not  necessarily 
fuller.  In  the  great  majority  of  cases,  indeed,  along  with  the  increased 
size  and  lengthened  visage,  there  is  a  decided  and  proportionate  loss  of  the 
roundness  and  fullness  presented  in  the  infantile  period.  The  reason  for 
this  is  obvious,  when  observing  the  great  prominence  of  the  nasal  and 
malar  bones,  and  the  corresponding  depressions  in  the  other  parts  of  the 
face,  particularly  the  canine  fossa3  of  the  superior  maxilla.  In  life,  when 
these  depressions  are  not  well  “padded  round  with  fat,”  the  cheeks  of 
course  present  a  wan  and  sunken  appearance.  In  the  series  here  pre¬ 
sented,  while  the  bones  of  the  face  have  gradually  increased  in  size,  those 
of  the  cranium  have  maintained  a  proportionate  relation.  This  promi¬ 
nent  ridge  in  particular,  (the  supra-orbital,)  in  the  frontal  bone  of 
this  very  fine  and  perfect  adult  skull,  and  which  has  much  to  do  with  ex¬ 
pression,  is  owing  to  the  gradual  separation  of  the  external  and  internal 
plates  of  the  os  frontis  at  this  point,  so  as  to  form  the  frontal  sinus.  On 
this  ridge  the  eyebrows  rest,  although  they  are  usually  described  as  rest¬ 
ing  on  the  superciliary  ridge ;  but  this  is  not  correct. 

It  is  generally  conceded  that  the  proportionate  relation  of  the  bones  of 
the  face  to  those  of  the  cranium  has  much  to  do  with  the  moral  and 
mental  qualities  of  the  individual ;  in  other  words,  that  .a  high  order 
of  intellect  is  usually  manifested  by  those  in  whom  the  cranium  is  large, 
the  forehead  broad  and  high,  and  the  bones  of  the  face  small ;  while  the 
animal  propensities  are  generally  evinced  in  a  marked  degree,  and  pre¬ 
ponderate  over  the  intellectual  in  those  with  depressed  foreheads,  com¬ 
pressed  temples,  and  large  and  massive  jaws,  as  in  the  case  of  this  emi¬ 
nently  prognathous  skull  of  an  African,  with  whose  antecedents  I  was 
made  acquainted  by  the  gentleman  who  presented  the  specimen  to  me. 
The  record  in  his  case  is  in  full  confirmation  of  the  position  just  advanced. 

The  opposite  extreme  is  sometimes  presented,  in  which  the  bones  of 
the  face  are  so  disproportionately  small,  in  comparison  with  the  cranium, 
as  to  constitute  a  marked  deformity.  Again,  a  want  of  harmony  between 
the  different  bones  of  the  face  is  occasionally  presented ;  as,  for  instance, 
when  the  inferior  maxilla  is  very  large  and  massive,  or  unusually  small, 
in  comparison  with  the  superior  maxilla,  or  vice  versa.  This  hyper¬ 
trophied  or  atrophied  condition  may  occur  in  any  of  the  bones,  and  of 
course  when  existing  will  mar  the  harmony  of  the  surrounding  parts. 

In  extreme  old  age,  the  atrophied  condition  of  the  jaws  (markedly 


10 


manifest  in  this  skull,  belonging  to  a  very  old  person)  due  to  the  gradual 
loss  of  all  the  teeth,  and  the  absorption  of  the  alveolar  processes,  pro¬ 
duces  that  decided  alteration  in  the  features  of  the  aged  with  which  we 
are  all  so  familiar.  The  change  which  invariably  takes  place  in  the 
angle  of  the  lower  jaw  in  consequence  of  the  disappearance  of  the  teeth 
and  processes,  causes  the  chin  to  project,  and  when  the  jaws  are  closed 
the  nose  and  chin  approximate  each  other.  Even  when  apart,  the  falling 
in  of  the  lips  so  encroaches  upon  the  oral  cavity  as  to  make  it  too  small 
for  the  tongue,  and  thus  renders  the  speech  feeble  and  indistinct  It  is 
here  where  the  skill  of  the  mechanical  dentist  finds  a  field  for  artistic  la¬ 
bor,  not  only  by  replacing  the  lost  expression  of  the  face,  but  also  by 
restoring  the  medium  through  which  the  wants  and  thoughts  of  the  indi¬ 
vidual  are  made  known  to  others. 

Arising  from  various  parts  of  the  bony  framework,  and  then  mainly 
converging  to  one  or  the  other  of  the  two  great  centres  of  expression, 
the  eyes  and  mouth,  there  are  a  number  of  muscles  on  whose  action  the 
varying  play  of  the  features  depends.  Intending  by  no  means  to  give,  at 
this  time,  a  lengthy  and  detailed  description  of  these  muscles,  but  rather 
to  notice  them  casually,  with  the  aid  of  the  drawings,  and  the  large  pa¬ 
pier-mache  manikin  here  presented,  I  hope  to  make  myself  clearly  under¬ 
stood.  We  will  commence  with 

The  Occipito  frontalis  (1,  2,  3,)  consists  of  two  broad  but  fleshy 
bellies,  with  an  intervening  aponeurosis  resting  upon  the  arch  of  the 
skull,  .and  over  which  it  slides ;  the  posterior  portion  of  the  muscle 
arises  from  the  superior  curved  line  of  the  occipital  bone.  The  prin- 


pal  parts  of  the  anterior  fibres  are 
inserted,  or  blend  with  the  corru- 
gator  supercilii,  and  the  superior 
j^argin  of  the  orbicularis  palpebra¬ 
rum.  The  minor  portions  of  the 
right  and  left  frontal  muscles  unite 
together  some  space  above  the  root 
of  the  nose,  and  are  inserted  at  this 
point  and  send  down  fibres  which 
are  continuous  with  the  pyramidalis 
nasse.  Function,  It  moves  the 
scalp,  elevates  the  eyebrows,  and 
induces  the  transverse  wrinkles  of 
the  forehead. 


The  Corrugator  Supercilii  lies 
under  the  occipito  frontalis,  and  is 


a  small,  pyramidal  muscle,  arising  from  the  inner  extremity  of  the  super- 


11 


ciliary  ridge;  its  fibres  proceed  outward  from  their  origin  and  blend  with 
those  of  occipito  frontalis  and  orbicularis  palpebrarum.  Function.  It 
draws  the  eyebrows  and  eyelids  inward,  and  produces  the  vertical  wrin¬ 
kles  of  the  forehead. 

The  Orbicularis  Palpebrarum  (4)  consists  of  a  thin,  flat  plane  of 
elliptical  fibres,  which  extend  around  the  whole  circumference  of  the 
orbit  and  eyelids.  It  spreads  outward  on  the  temple  and  downward  on 
the  cheek,  but  the  only  fixed  points  of  attachment,  however,  to  bone  are 
at  the  inner  margin  of  the  orbit.  Function.  It  closes  the  eyelids. 

The  Pyramidalis  Nasi  (5)  is  usually  regarded  as  a  prolonged  slip  of  the 
occipito  frontalis,  which  continues  downward  on  the  bridge  of  the  nose 
where  it  blends  with  the  compressor  nasi.  Function.  It  draws  down 
the  inner  angle  of  the  eyebrows,  and  produces  the  transverse  wrinkles  on 
the  bridge  of  the  nose. 

The  Levator  Labii  Superioris  Alseque  Nasi  (8)  is  a  thin,  triangular 
muscle,  arising  from  the  upper  part  of  the  nasal  process  of  the  superior 
maxilla  by  a  pointed  extremity,  and,  as  it  descends  along  the  side  of  the 
nose,  gradually  increases  in  breadth,  and  then  divides  into  two  slips,  one 
of  which  is  inserted  into  the  ala  of  the  nose,  and  the  other  blends  with 
the  orbicularis  oris.  Function.  It  elevates  the  upper  lip  and  ala  of 
the  nose,  and  dilates  to  a  considerable  extent  the  latter  organ. 

The  Compressor  Nasi  (6)  arises  narrow  and  fleshy  from  the  canine  fossae 
of  the  superior  maxilla,  and  its  fibres  continuing  upward  and  inward  ex¬ 
pand  into  a  thin  aponeurosis  which  unites  on  the  dorsum  of  the  nose 
with  that  of  the  muscle  of  the  opposite  side.  Function,  The  compressors 
may  act  either  as  dilators  or  as  constrictors  of  the  nares. 

Depressor  Labii  Superioris  Alseque  Nasi,  covered  by  the  orbicularis 
oris,  arises  from  the  myrtiform  fossae  of  the  superior  maxilla,  as  a  short 
radiating  muscle,  whose  fibres  diverge  upward  and  outward;  the  ascend¬ 
ing  fibres  terminate  in  the  septum  and  back  part  of  the  ala  of  the  nose; 
the  others  curve  forward  and  blend  with  the  upper  portion  of  the  orbic¬ 
ularis  oris.  Function.  It  draws  the  upper  lip  and  ala  of  the  nose  down¬ 
ward,  and  thereby  constricts  the  anterior  nares. 

The  Levator  Labii  Superioris  Proprius  (9)  arises  from  the  lower 
margin  of  the  orbit,  where  it  is  attached  partly  to  the  superior  maxilla, 
and  partly  to  the  malar  bone;  its  fibres  pass  downward  and  inward, 
and  blend  with  the  upper  part  of  the  orbicularis  oris.  Function.  It  is 
the  proper  elevator  of  the  upper  lip,  and  at  the  same  time  carries  it  a 
little  inward. 

The  Levator  Anguli  Oris,  covered  by  the  preceding  and  the  zygo- 
matici  muscles,  arises  from  the  canine  fossae  just  below  the  infra- orbital 
foramen,  and  its  fibres  pass  downward  and  outward  to  be  inserted  into 


12 


the  orbicularis  oris  at  the  angle  of  the  mouth.  Function.  It  raises  the 
angle  of  the  mouth  and  draws  it  inward. 

The  Zygomaticus,  Major  and  Minor,  (10,  11,)  arise,  the  latter  in  front 
of  the  former,  from  the  malar  bone,  and  then  pass  downward  and  outward 
to  the  upper  lip  and  angle  of  the  mouth,  where  their  fibres  blend  with 
the  orbicularis  oris.  Function.  They  raise  the  upper  lip  and  draw  the 
corners  of  the  mouth  outward,  as  in  laughing. 

The  Levator  Lahii  Inferioris  (14)  arises  from  the  incisive  fossae  of  the 
lower  jaw  external  to  the  symphysis ;  the  fibres  pass  downward  and  a 
little  forward  to  be  inserted  into  the  chin.  Function.  It  raises  and  pro¬ 
trudes  the  lower  lip. 

The  Depressor  Lahii  Inferioris  (12)  arises  from  the  oblique  line  of  the 
inferior  maxilla,  just  in  front  of  the  anterior  mental  foramen ;  it  is  a  quad¬ 
rilateral  shaped  muscle,  and  its  fibres  pass  upward  and  outward  to  be  in¬ 
serted  into  the  lower  lip.  Function.  It  draws  the  lower  lip  downward 
and  a  little  outward. 

The  Depressor  Anguli  Oris  (13)  arises  from  the  external  oblique  line 
of  the  lower  jaw  by  a  broad  base,  and  its  fibres  converge  as  they  pass  up¬ 
ward  to  be  inserted  into  the  angle  of  the  mouth,  where  they  unite  with 
the  orbicularis  oris,  the  zygomaticus  major,  and  the  levator  anguli  oris. 
Function.  It  draws  the  corners  of  the  mouth  downward,  and  is  the  an¬ 
tagonist  of  the  muscles  just  named ;  when  they  all  act  together,  the  mouth 
is  drawn  backward. 

The  Buccinator  (18)  is  a  broad,  thin  muscle,  arising  from  the  outer 
border  of  the  pterygo-maxillary  ligament,  and  the  external  surface  of  the 
alveolar  processes  of  the  upper  and  lower  jaw,  commencing  at  the  first  mo¬ 
lar  tooth  and  passing  backward.  The  fibres  of  the  muscles  converge,  and 
are  inserted  into  the  angle  of  the  mouth  and  the  upper  and  lower  lips. 
Function.  It  compresses  the  cheek,  so  as  to  assist  mainly  in  driving  air 
y  from  the  oral  cavity,  as  in  blowing  on  wind  instruments. 

The  Orbicularis  Oris  (I)  is  a  great  sphincter  muscle  surrounding  the 
mouth,  and  although  it  has  no  bony  origin  or  insertion,  as  we  have  found, 
a  large  number  of  muscles  arising  from  the  different  bones  of  the  face 
centre  here  and  blend  their  fibres  with  those  of  this  muscle.  Function. 
It  closes  the  lips. 

While  the  muscles  already  described  as  the  superficial  muscles  of  the 
.  face  are  mainly  concerned  in  the  varying  expressions  of  the  countenance, 
it  must  be  remembered  that  those  deep-seated  muscles,  the  temporal,  mas- 
seter,  and  external  and  internal  pterygoid,  which  are  the  active  agents  in 
the  comminution  of  food,  sometimes  play  an  important  part  in  expression. 
This  is  markedly  manifest  in  the  aged  after  the  loss  of  the  dental  organs, 
with  whom  the  shortening  of  the  face,  the  protrusion  of  the  jaw,  and  the 


13 


approximation  of  the  nose  and  chin,  under  such  circumstances,  are  due  to 
the  contraction  of  these  muscles  and  the  influence  which  they  exert  in 
modifying  the  shape  of  the  lower  jaw,  by  altering  the  angle  which  the 
ramus  forms  with  the  body  of  the  bone  in  early  manhood.  Considerations 
such  as  these  indicate  the  propriety  of  a  brief  description  of  these  mus¬ 
cles,  in  connection  with  the  subject  under  consideration.  The  first  of 
these, 

The  Temporalis,  arises  from  the  entire  temporal  fossae  and  forms  a 
broad,  radiating  muscle  whose  fibres,  as  they  descend,  converge  into  a 
flat  tendon  which  is  inserted  into  the  inner  surface  of  the  coronoid  process 
of  the  lower  jaw.  Function.  It  raises  the  lower  jaw. 

The  Masseter  (15)  is  a  quadrilateral-shaped  muscle,  and  arises  from  the 
malar  process  of  the  superior  maxillae  and  the  zygomatic  arch,  and  is 
inserted  into  the  posterior  third  of  the  outer  surface  of  the  body  of  the 
lower  jaw,  and  the  ramus  from  the  coronoid  process  to  the  angle.  It 
has  two  planes  of  fibres,  superficial  and  deep.  The  first  pass  downward 
and  backward,  the  second  downward  and  forward.  Function.  It  draws 
the  lower  jaw  upward  and  forward,  or  upward  and  backward. 

The  Pterygoideus  Externus  arises  (1)  by  two  heads  from  the  pterygoid 
ridge  of  the  great  ala  of  the  sphenoid  bone,  the  outer  surface  of  the  ex¬ 
ternal  plate  of  the  pterygoid  process,  and 
part  of  the  tuberosity  of  the  palate  bone; 
and  its  fibres  pass  horizontally  backward  and 
outward,  to  be  inserted  (2)  into  the  neck  of  the 
condyle  of  the  lower  jaw.  Function.  When 
the  two  muscles  act  together  they  draw  the 
inferior  maxilla  directly  forward,  so  as  to 
make  the  lower  front  teeth  project  beyond 
those  of  the  upper.  The  protrusion  of  the 
chin  in  those  who  have  lost  their  teeth  is 
greatly  due  to  this  fact.  The  lateral  sliding  motion  of  the  lower  jaw  in 
mastication  is  effected  by  the  alternate  contraction  of  the  muscles  of  the 
right  and  left  sides. 

The  Pterygoideus  Internus,  (3,)  like  the  masseter,  is  quadrilateral  in 
form,  and  arises  from  the  pterygoid  fossa  of  the  sphenoid  and  the  tuberosity 
of  the  palate  bones;  its  fibres  pass  outward,  downward,  and  backward,  to 
be  inserted  info  the  inner  surface  of  the  ramus  and  angle  of  the  lower  jaw. 
Function.  It  draws  the  lower  jaw  upward,  and,  from  the  obliquity  of  its 
fibres,  also  assists  the  pterygoideus  externus  in  carrying  the  jaw  forward 
and  from  side  to  side. 

There  are  other  muscles,  in  addition  to  those  just  described,  which  are 
somewhat  concerned  in  expression.  Among  these  are  the  depressors  of 


14 


the  lower  jaw  and  the  other  muscles  of  the  neck,  by  means  of  which  the 
head  is  thrown  into  various  positions,  under  the  influence  of  the  different 
passions;  but  it  would  be  foreign  to  the  subject  to  present  even  a  brief 
description  of  them.  It  is  proper,  however,  to  refer  to  the  ocular  group 
of  muscles,  for  the  eye  is  not  only  one  of  the  most  prominent  features  of 
the  face,  but  also  one  of  the  most  expressive.  When  the  rest  of  the  face 
is  so  completely  under  the  control  of  the  will  that  it  is  impossible  to  de¬ 
termine  what  is  passing  in  the  mind  of  another,  the  eye  frequently  reveals 
everything.  So  true  is  this  that,  when  the  tongue  says  one  thing  and  the 
eye  another,  men  of  observation  and  experience  invariably  believe  the 
latter.  It  is  the  position  of  the  organ,  whether  in  the  sidelong,  upward, 
or  downward  glance ;  the  fixed,  prolonged  gaze,  or  the  restless,  roving 
motion,  that  serves  as  a  key,  unlocking  to  the  mind  of  the  attentive  ob¬ 
server  that  which  another  is  striving  to  conceal.  The  muscles  by  which 
these  varied  movements  of  the  organ  are  effected  are  six  in  number,  and 
consist  of  two  groups,  the  first  of  which  are  four  straight  muscles,  the 
Rectus  Superior,  Inferior,  Externus,  and  Internus;  the  second  group 
is  formed  by  two  oblique  muscles,  the  Obliquus  Superior  and  Inferior. 
In  addition  to  moving  the  eye  upward  and  downward  and  from  side  to 
side,  if  all  the  muscles  of  either  group  act  together,  a  retraction  of  the 
eyeball  is  induced  by  the  contraction  of  the  Recti,  or  a  protrusion  of  the 
ball  by  similar  action  on  the  part  of  the  oblique.  Squinting  or  strabis¬ 
mus,  either  convergent,  looking  inward,  or  divergent,  looking  outward, 
which  gives  such  a  peculiar  expression  to  the  face,  is  due  to  a  want  of 
harmonious  action  in  the  ocular  group,  and  may  be  caused  by  overac¬ 
tion  or  paralysis  of  a  muscle  from  cerebral  disturbance ;  or  it  may  be  the 
result  of  imitation.  The  Levator  Palpebra,  which  is  included  in  this 
group,  is  the  elevator  of  the  eyelid. 

The  muscles  described,  like  the  bony  framework  on  which  they  rest, 
would  be  without  motion  but  for  their  connection  with  the  brain,  through 
the  medium  of  special  nerves,  whose  function  is  to  give  to  the  various 
parts  of  the  face  that  vitality  and  ever-changing  expression  which  consti¬ 
tutes  the  charming  attraction  of  the  human  countenance. 

Of  the  twelve  pair  of  cranial  nerves,  five  pair  are  concerned  in  expres¬ 
sion,  and  three  of  them  are  distributed  to  and  give  motion  to  the  muscles 
of  the  eye.  Thus  the  third  pair  of  nerves,  or  the  motor  oculi,  sends 
branches  to  all  of  these  muscles,  with  the  exception  of  the  motor  externus 
and  the  obliquus  superior,  to  the  first  of  which  pass  the  fourth  pair, 
or  motor  externus  nerve,  and  the  second  is  connected  with  the  sixth 
padr,  or  Nervus  Pathetici. 

The  and  seventh  pair  of  nerves  are  distributed  to  the  muscles  of 
the  face;  the  latter,  also  named  portio  dura,  or  facial,  emerges  from 


15 


the  stylo-mastoid  foramen,  and  then,"  passing  through  the  parotid  gland, 
is  eventually  distributed  exclusively  to  the  superficial  muscles  in  the  form 
of  a  plexus,  named  pes  anserinus.  It  is  purely  a  motor  nerve,  upon  the 
integrity  of  which  the  expression  of  the  countenance  and  the  varied  play 
of  the  features  depend.  This  has  been  demonstrated  in  the  most  satis¬ 
factory  manner  by  experiments  on  animals  and  in  pathological  conditions 
in  man.  Strange  as  it  may  appear  now,  it  was  formerly  supposed  that 
the  painful  affection  named  tic  Douleureux  was  seated  in  this  nerve,  and 
resection  of  it  at  the  stylo-mastoid  foramen  was  frequently  performed  for 
the  relief  of  patients,  but  with  no  other  result  than  inducing  paralysis  of 
the  superficial  muscles  and  loss  of  expression  on  the  side  of  the  face  oper¬ 
ated  upon,  the  patients  being  unable  to  close  the  eyelid,  elevate  the  ala 
nasi,  or  move  the  cheek  or  that  side  of  the  lips,  and  yet  at  the  same  time 
still  suffering  as  much  from  the  disease.  Paralysis  of  this  nerve  is  some¬ 
times  induced  by  cerebral  disturbance  or  the  presence  of  a  tumor  beneath 
the  ear,  and  is  usually  denominated  Bell’s  palsy,  on  account  of  the  true  ' 
nature  of  the  affection  having  been  made  known  by  Sir  Charles  Bell,  to 
whose  genius  and  laborious  experimental  research  the  world  is  greatly 
indebted,  not  only  for  their  kn|)wledge  of  this  disease,  but  also  for 
much  that  is  known  at  present  of  the  nervous  system.  Paralysis  of  the 
Portio  Dura  does  not  affect  in  the  slightest  degree  the  function  of 
temporal  masseter  or  pterygoid  muscles,  (and  therefore  interfere  with 
mastication,)  as  they  derive  their  nerve  force  from  the  motor  branch 
of  the  fifth  pair.  The  dependency  of  these  muscles  on  the  motor  branch 
of  the  fifth  can  be  readily  demonstrated  by  divisions  of  the  nerve  on  each 
side  in  animals,  when  the  lower  jaw  at  once  falls,  and  the  subject  oper¬ 
ated  upon  is  rendered  incapable  of  raising  the  jaw  or  masticating  its  food. 

If  the  nerve  of  one  side  only  is  cut,  the  parallelism  of  the  jaw  is  destroyed; 
or,  in  other  words,  the  muscles  of  the  side  operated  upon  being  paralyzed, 
fail  to  bring  the  jaw  in  contact  with  the  upper,  while  on  the  sound  side 
it  is  effected  as  usual. 

Premising  that  sufficient  has  been  said  with  regard  to  the  points  already 
touched  upon,  we  will  now  pass  to  the  consideration  of  some  of  the  ex¬ 
pressions  presented  by  the  countenance  when  under  the  influence  of  the 
different  passions  that  affect  the  mind  of  man.  It  is  impossible  to  de¬ 
scribe  all  of  these;  and  the  attempt,  at  best,  in  the  consideration  of  those 
to  which  your  attention  will  be  directed,  must  of  necessity  be  merely  sug¬ 
gestive  to  you  of  an  interesting  and  instructive  subject  of  study,  which 
for  years  has  more  or  less  intuitively  engaged  my  attention  :  whether 
when  in  conversation  with  others,  quietly  observing  them  when  engaged 
in  the  pursuit  of  business  or  pleasure ;  or  watching  the  delineations  of  the 
orator,  the  actor,  the  artist;  and  last,  though  not  least,  the  truthful  rev¬ 
elations  of  the  photograph. 


16 


In  illustration  of  this  part  of  the  subject,  I  shall  employ  a  number  of 
drawings,  here  presented,  portraying  the  different  expressions,  which  are 
faithful  copies  of  the  admirable  engravings  in  Sir  Charles  Bell’s  work  on 
the  Anatomy  and  Philosophy  of  Expression,  and  I  not  only  cordially 
acknowledge  the  pleasure  derived  from  the  perusal  of  his  eloquent  work, 
but  shall  be  most  happy  if  in  the  following  remarks  I  succeed  in  present¬ 
ing  a  fair  synopsis  of  his  extended  description  of  the  subject  in  connec¬ 
tion  with  my  own  observations  and  thoughts. 

All  the  facial  expressions  may  be  classified  under  two  heads — the  ex¬ 
hilarating  apd  the  depressing ;  and  the  angle  of  the  mouth  and  the  inner 
extremities  of  the  eyebrows  as  points  where  a  number  of  muscles  concen¬ 
ter  are  the  most  movable  parts  of  the  face,  and  on  whose  changes  expres¬ 
sion  chiefly  depend.  No  better  illustration  of  this  fact  can  be  afforded 
than  in  the  caricature,  with  which  every  one  is  familiar,  representing  two 
faces  joined  together,  in  one  of  which  the  elevation  of  the  angles  of  the 
mouth  gives  a  most  joyous  expression  to  the  face;  on  reversing  or  turn¬ 
ing  the  picture  upside  down,  however,  depression  of  the  same  mouth  at 
the  angles  produces  a  correspondingly  despondent  expression  in  the  other 
face.  ^ 

Commencing  with  laughter,  you  will  observe  in  this  picture  that  the 
various  muscles  which  have  been  described  as  inserted  into  the  orbicu¬ 
laris  oris,  have  entirely  overcome  the  action  of  that  muscle  whose  func¬ 
tion  is  to  close  the  lips.  When  a  ludicrous  idea  enters  the  mind,  as  a 
general  thing  it  is  in  vain  to  try  to  keep  the  mouth  closed.  The  antago¬ 
nistic  muscles  concentering  there  exert  a  force  beyond  all  control,  and 
frequently  the  more  determined  the  effort  not  to  give  way  to  the  inclina¬ 
tion,  the  more  marked  and  explosive  eventually  becomes  the  demonstra¬ 
tion.  The  elevator  muscles,  inserted  in  the  upper  lip  and  the  angles  of 
the  mouth  as  the  active  agents  in  drawing  the  mouth  upward,  produce  a 
fullness  of  the  cheeks  which,  pressing  upon  the  lower  eyelids,  throws  the 
skin  into  wrinkles  under  them.  At  the  same  time  the  teeth  are  exposed; 
while  by  the  contraction  of  the  orbicularis  palpebrarum  the  eyes  are 
almost  concealed,  and,  by  compression  of  the  lachrymal  gland,  frequently 
suffused  with  tears.  Together  with  this,  the  agitation  of  the  muscles  of 
the  throat,  neck,  chest,  and  diaphragm  produce  audible  cachinations. 

In  the  reverse  of  this,  or  weeping,  the  lips  are  drawn  apart  by  the  con- 
verging  muscles,  but  in  place  of  the  elevation  of  the  corners  of  the  mouth 
they  are  now  drawn  downward  by  the  depressor  anguli  oris;  the  nostrils, 
at  the  same  time,  are  dilated,  and  the  tears  flow  profusely  from  under  the 
convulsively-closed  eyelids  over  the  flushed  cheeks;  while  the  veins  of  the 
forehead  are  distended  and  the  inner  part  of  the  eyebrows  are  drawn  up¬ 
ward  and  inward  by  the  combined  action  of  the  corrugator  supercilii 


0 


IT 

and  the  occipito-frontalis.  The  muscles  of  the  throat,  chest,  and  dia¬ 
phragm  are  spasmodically  affected  and  the  respiration  is  frequently  inter¬ 
rupted  by  sobs. 

Bodily  pairiy  the  manifestation  of  which,  in  the  face  of  our  patients,  is 
to  us  frequently  an  important  means  of  diagnosis,  not  only  in  children, 
but  those  of  a  larger  growth,  is  a  condition  that  particularly  claims  our 
attention  from  a  professional  and  humanitarian  point  of  view.  Here  let 
me  say,  in  passing,  that  pain  is  by  no  means  what  it  is  usually  regarded, 
an  unmixed  evil.  Paradoxical  as  the  statement  may  appear,  it  is  fre¬ 
quently  a  blessing  rather  than  a  curse,  as  it  is  the  chief  means  by  which 
we  become  aware  that  some  important  organ  is  diseased.  Without  such 
intimation,  the  part  affected  might  have  become  disorganized  to  such  an 
extent  as  not  only  to  destroy  the  function  of  the  organ,  but  also  to  place 
even  life  itself  in  jeopardy.  This  applies  with  peculiar  force  to  those 
organs  which  it  is  our  duty  to  save;  for  it  is  the  unpleasant  sensation  of 
pain  which  generally  drives  our  patients  to  us,  and  it  is  the  various  mani¬ 
festations  induced  by  the  pain  endured  which  enables  the  experienced 
practitioner  to  determine  the  nature  and  extent  of  the  difficulty. 

,  In  extreme  pain,  (except  in  cases  where  the  patient  is  suffering  from 
periodontitis,  when  the  occlusion  of  the  jaws  intensifies  the  suffering,)  the 
teeth  are  brought  together  with  great  force  and  ground  against  each 
other  by  the  temporal,  masseter,  and  pterygoid  muscles;  the  saliva  fre- 
•  quently  flows  in  large  quantities  from  the  mouth,  which  is  drawn  open 
laterally ;  the  face  is  flushed,  the  veins  distended,  the  nostrils  dilated,  the 
eyebrows  raised,  the  forehead  thrown  into  horizontal  wrinkles,  the  eyelids 
widely  opened,  and  the  tears' coursing  over  the  cheeks,  betray,  in  the 
most  unmistakable  manner,  the  suffering  endured. 

In  fear,  the  head  sinks  backward  between  the  elevated  shoulders;  the 
eyes  are  fixed  and  staring;  the  eyebrows  are  raised  to  their  utmost  by 
the  occipitofrontalis,  which,  in  addition  to  a  contracted  state  of  the  scalp, 
causes  the  hair  to  stand  on  end;  the  face  is  ghastly  pale,  and  the  cheeks 
hollow,  shrunken,  and  in  convulsive  motion,  like  lips  which  are  wide  open, 
owing  to  the  dropping  of  the  lower  jaw;  the  breathing  is  shorty  labored, 
and  spasmodic. 

In  rage,  the  inflamed  and  glaring  eyeballs,  owing  to  the  contraction  of 
the  oblique  muscles,  seem  ready  to  dart  from  their  sockets;  the  brow  is 
thrown  into  deep  vertical  wrinkles  by  the  corrugators ;  the  nostrils  are 
dilated;  while  through  the  clinched  teeth  but  open  mouth  words  of  hate 
are  delivered  with  emphatic  force. 

In  joy,  the  face  is  lighted  up  with  a  smile  by  the  gentle  elevation  of 
the  eyebrows,  the  lively  and  sparkling  appearance  of  the  eye,  and  the 
pleasant  expression  of  the  mouth,  which,  without  being  separated,  is 
drawn  aside  at  the  corners.  v 


Conscious  of  the  time  already  absorbed,  and  desiring  to  hear  from  some 
of  the  gentlemen  who  are  present  from  a  distance,  we  will  pass  over  the 
consideration  of  other  facial  expressions  which  might  be  referred  to,  trust¬ 
ing  that  those  which  have  been  so  hurriedly  described  may  awaken  a 
desire  on  the  part  of  all  to  acquire  a  thorough  and  accurate  knowledge 
of  the  entire  subject,  and  to  make  that  practical  application  of  the  knowl¬ 
edge  thus  gained  of  which  it  is  susceptible,  but  which  it  does  not  come 
within  the  province  of  this  address  to  make. 


THE 


TEETH 

IN  THEIR 

RELATIONS  TO  MASTICATION,  SPEECH,  AND  APPEARANCE.^ 

An  Address  delivered  before  the  Delaware  Dental  Association. 


Gentlemen  : — In  compliance  with  your  appointment  I  appear  before 
you  this  evening, — not,  however,  as  an  essayist,  for  my  time  has  been  so 
much  engrossed  by  various  duties  since  the  nomination  as  to  preclude 
the  possibility  of  preparing  a  written  address,  but  rather  in  an  oral  com¬ 
munication,  which  to  me,  from  years  of  habit  in  the  lecture-room,  is  de¬ 
cidedly  preferable,  to  invite  your  attention  to  the  consideration  of  the 
Human  Teeth  in  their  Relations  to  Mastication^  Speech,  and  Appear¬ 
ance. 

The  varied  and  extended  character  of  the  subject  demands  that  it 
should  be  treated  in  a  general  and  suggestive  manner;  and  my  object  in 
selecting  it  was,  that  it  might  awaken  a  spirit  of  inquiry  in  these  various 
directions,  and  that  the  knowledge  thus  obtained  might  be  made  instru¬ 
mental  in  securing  to  patients  beneficial,  practical  results. 

To  prevent  confusion  and  secure  clearness  of  conception,  it  will  be 
advisable  to  consider  the  subject  under  separate  heads,  commencing  with 
the  first. 

Mastication. — It  may  be  truly  said  that  a  just  appreciation  of  the 
position  which  the  human  teeth  occupy  as  masticating  agents,  can  only 
be  obtained  by  familiarity  with  the  comparative  anatomy  of  the  dental 
organs ;  for  in  the  structure  of  the  teeth  there  are  certain  characteristic 
differences,  corresponding  with  the  habits  of  the  animal  and  the  kind  of 
food  upon  which  it  subsists;  and  in  the  mouth  of  man  teeth  are  found 
belonging  to  different  classes  of  animals,  whose  habits  and  food  are  of  the 
most  opposite  character.  In  illustration  of  this  point,  the  craniae  of  man 
and  various  animals,  lying  on  the  table,  are  presented. 

The  illustrations  accompanying  this  communication  were  engraved  from  speci¬ 
mens  in  my  possession. — J.  H.  McQ. 


3 


(19) 


20 


With  regard  to  the  entire  animal  series,  the  teeth  may  be  defined  as 
hard  organs  situated  on  the  inner  surface  of  the  digestive  canal,  varying 
in  shape,  size,  number,  and  location,  with  the  character  of  the  materials 
which  they  are  intended  to  comminute.  By  some  animals  they  are  em¬ 
ployed  as  offensive  and  defensive  weapons  in  prehension ;  by  others,  as 
organs  of  locomotion;  again,  they  are  used  by  certain  kinds  of  fish  in 
crushing  the  stony  shells  inclosing  their  food;  as  in  the  case  of  the 
sheep^ s-head  fish  and  the  parrot-fish,  {scari.) 

Although  man  and  several  of  the  animals  have  thirty-two  teeth  belong¬ 
ing  to  the  permanent  set,  the  typical  number  of  the  vertebrates  is  forty- 
two.  Some  of  them,  however,  are  edentulous,  or  without  teeth ;  others 
have  but  one  tooth,  and  from  this  they  range  upward  to  such  a  large 
number,  that  to  those  who  have  not  examined  the  subject,  it  must  appear 
incredible.  Thus  birds  are  found  invariably  edentulous,  the  gizzard 
serving  as  the  comminuting  organ ;  while  at  the  other  extreme,  fish 
are  supplied  in  the  most  liberal  manner  with  teeth.  In  many  of  the 
vertebrates  the  teeth  are  firmly  implanted  in  the  maxillary  and  pre¬ 
maxillary  bones.  In  other  cases,  as  in  certain  kinds  of  fish,  the  teeth  are 
inserted  not  merely  in  the  maxillary  and  premaxillary  bones,  but  in  the 
palate  bones,  vomer,  pharynx,  on  the  tongue,  and  in  the  stomach ;  being 
so  numerous,  and  in  such  peculiar  positions,  that  it  is  quite  difficult  to 
count  them ;  running  as  high  as  one  hundred  and  forty  in  some,  and  in 
others  to  one  hundred  and  ninety,  and  beyond.  Wherever  found,  while 
they  may  subserve  other  purposes,  they  are  invariably  necessary  agents 
in  the  prehension  or  comminution  of  food. 

In  fish  and  serpents,  with  the  exception  of  the  poison-fangs  of  ven¬ 
omous  reptiles,  the  teeth  are  merely  organs  of  prehension,  and  prevent 
the  escape  of  the  prey  after  being  seized ;  and  which,  as  a  general  thing, 
is  swallowed  entire. 

The  comparative  anatomist,  in  making  the  diet  a  means  of  classifica¬ 
tion — as  in  the  carnivorous  and  herbivorous  animals — takes  advantage  of 
certain  marked  characteristics  in  the  digestive  apparatus  to  divide  these 
animals.  These  peculiarities,  however,  are  not  confined  to  the  dental  or¬ 
gans  only,  but  a  constant  relation  is  maintained  between  the  shape  and 
structure  of  the  teeth;  the  articulation  of  the  jaw;  the  form  of  the 
stomach ;  the  length  of  the  intestines,  and  the  nature  of  the  food  on 
which  the  animals,  subsist. 

Thus  the  teeth  of  the  truly  carnivorous  animals  are  fitted  to  seize  their 
prey  and  lacerate  the  food,  but  not  to  thoroughly  masticate  it.  These 
organs  are  of  three  kinds,  and  adapted  to  different  mechanical  purposes. 
Thus,  in  the  polar  bear,  the  incisors — six  in  the  superior  and  six  in 
the  inferior  maxillae — are  so  formed  and  situated  as  to  serve  as  shears 


21 


in  dividing  the  food.  The  canines — two  above  and  two  below — long, 
curved,  and  sharp-pointed  tusks,  possessing  great  strength,  and  deeply 
and  firmly  implanted  in  the  jaws,  are  used  by  the  animal  as  offensive  and 
defensive  weapons,  and  for  seizing  upon  and  holding  its  struggling  prey. 
The  molars — four  on  each  side,  above  and  below — have  cutting  or  trench¬ 
ant  crowns,  with  serrated  edges  and  sharp  points,  which  are  arranged  in 
a  direction  parallel  with  the  line  of  the  jaw  ;  and  the  superior  teeth  have 
a  flat  inner  side,  against  which  the  inferior  works  like  a  scissor-blade. 


POLAR  BEAR. 


These  teeth  serve  to  mangle  rather  than  thoroughly  comminute  the  food 
of  the  animal.  The  jaws  are  strong,  and  the  deep  and  narrow  glenoid 
cavities  in  the  temporal  bones  receive  the  condyloid  processes  of  the  in¬ 
ferior  maxillge  in  such  a  manner  as  not  to  admit  of  any  horizontal  motion, 
either  backward  or  forward,  or  from  side  to  side.  This  articulation, 
constituting  the  pure  ginglymous,  or  hinge-like  joint,  affords  the  lower 
jaw  only  the  upward  and  downward  movements.  In  addition  to  this,  the 
wide  and  deep  temporal  fossae  give  an  extensive  origin  to  the  immense 
temporal  muscles  inserted  into  the  coronoid  processes  of  the  lower  jaw ; 
and  the  zygomatic  processes  are  very  strong  and  prominent,  and  the 
masseter  muscles  arising  from  them,  and  inserted  into  the  rami  and  body  of 
the  lower  jaw,  are  large,  broad,  and  powerful ;  while  the  pterygo-maxillary, 
and  pterygoid  fossm,  giving  origin  respectively  to  the  external  and  inter¬ 
nal  pterygoid  muscles,  are,  comparatively  speaking,  quite  shallow,  and  the 
muscles  small.  By  this  arrangement  in  the  shape  and  position  of  the 
teeth,  the  articulation  of  the  jaw,  and  the  origin  and  insertion  of  the 
muscles,  the  animal  is  enabled  to  seize  upon  and  hold  its  prey.  Any 
other  kind  of  joint,  under  such  circumstances,  would  prove  not  merely 
unreliable,  but  actually  worthless.  In  the  carnivora  the  stomach  is  sim¬ 
ple,  and  the  intestinal  canal  is  remarkably  short  in  relation  to  the  length 
of  the  body. 

Passing  to  the  herhivora,  and  selecting  the  horse  as  an  example  of 
this  class,  the  incisors— six  in  number  in  both  jaws— are  arranged  in  a 


22 


curve  at  the  anterior  end  of  the  jaws,  and  are  employed  as  prehensile  , 
organs  in  seizing  upon  and  cutting  off  the  herbage  on  which  the  animal 
subsists.  The  canines,  small  in  the  horse,  and  rudimental  in  the  mare, 
are  situated  in  the  upper  jaw,  in  the  middle  of  the  long  interspace  between 
the  incisors  and  molars,  while  in  the  lower  jaw  they  are  close  to  the  outer 
incisors.  They  subserve  no  purpose  in  mastication,  this  being  effected 
altogether  by  the  molars, — these  are  six  in  number,  for  each  side  of  the 
upper  and  lower  jaws, — and  the  crowns  of  which  present  two  double 
crescents,  the  convexity  being  turned  inward  in  the  upper  and  outward  in 


MOLARS  OF  HORSE. 


the  lower  ones.  In  addition  to  this,  the  triturating  surface  is  found  to 
present  a  series  of  inclined  planes,  leading  from  prominent  ridges  to  large 
hollow  cavities  lying  at  their  base ;  the  inequalities  thus  presented  being 
due  to  the  unequal  wear  of  the  different  tissues  composing  the  crown. 
The  grass,  either  in  a  green  or  dry  state,  on  which  the  herbivora  subsist, 
containing  as  it  does  large  quantities  of  pure  silica  or  flint,  produces 
decided  abrasion  of  the  teeth,  particularly  the  molars.  If  the  teeth, 
although  presenting  a  rough  masticating  surface  when  first  erupted,  had 
been  composed  of  only  one  tissue,  they  would  soon  have  worn  smooth, 
and  proved  inadequate  to  the  service  demanded.  To  meet  this  emer¬ 
gency,  therefore,  the  different  tissues  composing  the  teeth — the  enamel, 
dentine,  and  cementum — are  arranged  on  the  same  plane.  By  such  a 
contrivance  the  teeth  necessarily  wear  unequally,  and  always  present  a 
rough,  uneven,  grinding  surface  to  the  food. 

The  glenoid  cavities  in  the  temporal  bones  of  the  horse  and  herbivorous 


V 


23 


animals  generally  are  quite  shallow,  and  the  condyloid  processes  of  the 
lower  jaw  rounded.  The  joint  thus  formed  not  only  admits  of  upward 
and  downward  movements,  but  also  of  extensive  sliding  motions  in  every 
direction.  In  addition  to  this,  the  temporal  fossae  are  quite  narrow  and 
shallow,  the  zygomatic  processes  not  very  prominent,  and  the  temporal 
and  masseter  muscles  arising  from  them  are  feeble,  in  comparison  with  those 
of  the  carnivora.  The  pterygo-maxillary  and  pterygoid  fossae,  however,  are 
quite  deep,  and  the  external  and  internal  pterygoid  muscles  arising  there¬ 
from  largely  developed.  By  the  action  of  these  muscles  the  horizontal  rub¬ 
bing  motion  of  the  roughened  surfaces  of  the  superior  and  inferior  molars 
against  each  other  is  effected,  and  the  coarse  articles  of  food  are  thoroughly 
triturated  and  reduced  to  a  pulpy  mass.  One  order  of  the  herbivora — the 
ruminantia — possesses  the  faculty  of  returning  the  food  to  the  mouth 
and  subjecting  it  to  remastication,  after  it  has  been  once  swallowed. 


This  is  due  to  the  remarkable  arrangement  and  action  of  the  stomach, 
which,  as  in  the  cow  for  instance,  is  of  immense  size,  and  divided  into 
four  compartments  or  stomachs.  Another  marked  peculiarity  of  this 
order  is  the  absence  of  incisors  and^  canines  in  the  upper  jaw.  The 
animal,  when  feeding,  after  slightly  bruising  the  coarse  vegetation  by  a 
first  mastication,  swallows  the  bolus,  which  passes  along  the  oesophagus 
to  the  paunch  or  first  stomach,  and  then  by  small  portions  to  the  second 
stomach,  where,  after  being  subjected  to  an  elevated  temperature  for  some 
time  and  mixed  with  the  secretions,  portions  of  it  are  compressed  into 
little  pellets,  which  successively  ascend  to  the  mouth,  to  be  rechewed ; 
after  this  is  thoroughly  effected,  the  food  is  again  swallowed,  and  passes 
on  to  the  third  stomach,  a  channel  being  formed  through  the  first  two  by 
the  contraction  of  the  groove  or  gutter  made  by  the  prolongations  of  the 
oesophagus;  here  it  remains  a  certain  length  of  time,  and  then  passes 
into  the  fourth  stomach,  the  true  digesting  organ,  which  is  analogous  to 
the  simple  stomach  of  animals  in  general. 


24 


In  man  the  teeth  occupy  a  position  intermediate  to  those  of  the  car¬ 
nivorous  and  herbivorous  animals.  Twelve  of  the  teeth,  viz.,  the  canines 
and  the  bicuspids,  correspond  to  those  of  the  former;  and  twenty,  the 
incisors  and  molars,  to  those  of  the  latter.  The  canines,  however,  are 
much  less  prominent  and  pointed  than  in  the  carnivora;  and  the  molars, 
while  they  resemble  those  of  the  herbivora,  in  being  thick  and  strong 
and  presenting  comparatively  flat  surfaces,  at  the  same  time,  in  place  of 
the  curvilinear  ridges  of  the  herbivora,  have  more  or  less  conical  emi¬ 
nences  like  those  of  the  carnivora. 


HUMAN  TEETH. 


The  form  of  the  articulation  of  the  lower  jaw  and  the  organs  of  diges¬ 
tion,  not  less  than  the  teeth,  present  strong  evidence  that  man  is  truly 
omnivorous,  and  afford  a  clear  physiological  argument  in  favor  of  the 
mixed  animal  and  vegetable  diet  which  custom  and  tastd  have  decided  to 
be  natural  for  the  human  species ;  while  the  vegetarian  theory,  which 
rigidly  excludes  everything  like  animal  food,  under  all  the  varying  cir¬ 
cumstances  of  climate  and  temperature,  is  in  opposition  to  the  indications 
afforded  not  only  by  the  structure,  but  also  by  the  practice  of  man. 
Millions,  it  is  true,  avoid  flesh  altogether,  but  millions  also  use  it  exten¬ 
sively.  In  the  torrid  zone  there  is  little  or  no  occasion  for  its  employ¬ 
ment,  while  in  the  cold  climates,  particularly  in  the  frigid  zone,  it  is 
imperatively  demanded ;  and  there  is  no  fact  more  incontrovertible  than 
that  the  highest  order  of  physical  and  mental  development  is  found  in 
those  countries  where  the  inhabitants  unite  animal  with  vegetable  food. 


25 


As  there  are  cutting,  tearing,  and  grinding  teeth  in  man,  so  the  articula¬ 
tion  of  the  lower  jaw  is  intermediate  to  those  of  the  animal  and  vege¬ 
table  feeder.  Thus  the  transverse  condyles  of  the  jaw  are  received  into 
the  glenoid  cavities,  so  as  to  admit  of  not  only  upward  and  downward, 
but  also  of  considerable  lateral  or  sliding  motion;  and  the  temporal, 
masseter,  and  pterygoid  muscles  effecting  this,  and  the  temporal  fossae, 
zygomatic  processes,  and  the  pterygo,  maxillary,  and  pterygoid  fossae  from 
which  these  muscles  arise,  hold  the  same  intermediate  relation  to  the 
animals  already  referred  to.  By  this  arrangement  the  act  of  mastication 
in  man,  unlike  the  simple  laceration  of  the  food  on  the  part  of  the  car¬ 
nivora,  can  be  as  perfectly  effected  as  in  the  herbivora;  and  although 
the  articles  of  diet  are,  to  a  great  extent,  freed  from  impurities  and  soft¬ 
ened  by  cooking,  this  should  be  done ;  for,  while  some  human  beings  are 
in  the  habit  of  bolting  their  food,  indulgence  in  such  a  practice  is  inva¬ 
riably  followed  by  the  most  unpleasant  results.'  The  human  stomach  in 
nowise  resembles,  as  the  practice  of  some  would  seem  to  indicate,  the 
gizzard  of  birds,  where  hard  and  otherwise  indigestible  substances  can  be 
triturated ;  nor  does  it  possess  the  faculty  of  returning  imperfectly  mas¬ 
ticated  food  to  the  mouth  for  a  second  and  thorough  comminution,  as 
in  the  ruminantia ;  neither  is  it  like  the  stomach  of  the  carnivora,  which 
frequently  digests  with  ease  large  portions  of  bone;  but  it  is  so  constitu¬ 
ted  as  to  demand  the  most  perfect  and  minute  division  of  the  food  in  the 
mouth.  It  .is  truly  said  that  food  well  chewed  is  half  digested.  If,  in 
place  of  this,  it  is  swallowed  in  undivided  masses,  it  becomes  a  source  of 
irritation  by  remaining  a  long  time  undissolved  in  the  stomach;  and,  if 
this  practice  is  continued  for  any  length  of  time,  dyspepsia,  with  its  at¬ 
tendant  train  of  horrors,  is  evoked.  The  Americans,  in  their  all-absorb¬ 
ing  pursuit  of  business  or  pleasure,  perhaps  more  than  any  other  people 
on  the  globe,  violate,  in  the  most  reckless  manner,  this  canon,  and,  as  a 
consequence,  lantern  jaws  and  disordered  stomachs  are  universally  pre¬ 
sented  to  view.  If  more  time  was  devoted  to  the  thorough  mastication 
of  the  food,  in  place  of  being  time  wasted,  it  would  result  in  increased 
comfort,  physical  and  mental  power  and  endurance,  and  length  of  years. 

Passing  now  to  the  second  section  of  our  subject,  or  the  consideration 
of— 

Speech,  it  will  be  advisable,  in  the  first  place,  to  define  the  exact  differ¬ 
ence  between  voice  and  speech;  for  it  is  a  common  error,  even  among 
persons  of  education,  to  speak  of  them  as  if  they  were  one  and  the  same 
thing,  and  yet  that  such  is  not  the  case  will  be  evident  on  the  slightest 
reflection. 

Voice  is  possessed  not  only  by  man  but  also  by  all  of  the  vertebrata  having 


26 


lungs,  and  it  results  from  the  vibrations  induced  in  the  vocal  chords  as 
the  air  expelled  from  the  lungs  passes  through  the  glottis.  The  sound 
thus  created  is  capable  of  being  variously  modified  during  and  after  its 
production,  and  it  is  owing  to  the  mutations  induced  by  the  motions  of 
the  pharynx,  the  velum,  the  tongue,  the  lips,  and  other  parts  of  the 
mouth,  that  speech  or  articulated  voice  is  produced  in  man,  and  in  con¬ 
nection  with  his  moral  and  mental  endowments  places  him  above,  and  gives 
him  dominion  over  the  brute  creation,  and  enables  him  not  only  to  make 
known  his  wants,  experience,  and  thoughts  to  his  fellow-man  in  his  own 
day  and  generation,  but  also  by  the  aid  of  the  written  and  printed  record 
to  transmit  them  from  age  to  age,  thus  insuring  the  constant  and  pro¬ 
gressive  development  of  man's  moral  and  mental  powers,  and  contributing 
to  his  physical  comfort  and  well-being. 

In  the  construction  of  the  vocal  organs  in  man  nature  appears  to  have 
combined  the  double  mechanism  of  wind  and  string  instruments,  and  it  is 
on  this  account  that  it  surpasses  all  musical  instruments,  by  the  extent, 
the  perfection,  and,  above  all,  by  the  inexhaustible  variety  of  its  effects. 
Advantage  is  taken  of  the  function  of  respiration  to  convert  into  a  sound¬ 
ing  instrument  the  passages  formed  by  the  trachea  and  larynx,  through 
which  the  air  is  admitted  to  and  expelled  from  the  lungs.  The  larynx 
is  a  sort  of  cartilaginous  box  placed  at  the  upper  end  of  the  trachea,  and 
is  composed  of  five  distinct  pieces,  the  thyroid,  the  two  arytenoid,  the 
epiglottis,  and  the  cricoid  cartilages,  which  are  readily  moved  on  each 
other  by  appropriate  muscles. 

The  thyroid,  which  forms  the  uppe^r  and  fore  part  of  the  larynx,  con¬ 
sists  of  two  lateral  wings  of  a  quadrangular  shape,  united  in  front  in  a 
longitudinal  angle,  which  gives  the  prominence  to  the  fore  part  of  the 
throat,  observable  in  men,  named  pomurn  Adami.  From  the  posterior 
corners  of  the  wings  four  processes  project,  which  are  called  the  superior 
and  inferior  cornua.  The  cricoid  cartilage,  below  and  behind  the  thy¬ 
roid,  is  shaped  somewhat  like  a  signet  ring,  the  narrow  part  being  in 
front.  The  arytenoid  cartilages,  much  smaller  than  these,  and  of  a  py¬ 
ramidal  shape,  are  placed  one  on  each  side  on  the  upper  posterior  and 
lateral  parts  of  the  cricoid.  In  other  words,  the  cricoid  serves  as  a 
base  on  which  the  thyroid  and  the  two  arytenoides  execute  the  motions 
by  which  the  glottis  is  contracted  or  enlarged.  The  epiglottis,  resembling 
the  leaf  of  an  artichoke,  is  attached  by  its  base  to  the  upper  and  fore  part 
of  the  thyroid,  and  hangs  backward  over  the  glottis,  which  it  closes  in 
the  act  of  swallowing. 

These  cartilages  are  connected  with  each  other  by  ligaments,  the  most 
important  and  interesting  of  which  are  the  thy ro -arytenoid,  which  stretch 
from  the  base  of  the  arytenoid  cartilages  to  the  angle  between  the  wings 


27 


of  the  thyroid;  these  constitute  the  vocal  chords,  and  the  aperture  be¬ 
tween  them  named  the  glottis,  as  already  stated,  is  the  point  where  the 
breath  is  vocalized,  or  rendered  not  only  sonorous  but  also  modulated  in 
its  pitch.  In  the  adult  male  the  length  of  this  fissure  is  from  ten  to  eleven 
lines,  and  it  is  from  two  to  three  lines  wide  where  the  width  is  greatest. 
The  dimensions  are  much  less,  however,  in  the  female  and  in  boys  prior 
to  puberty,  bearing  the  proportion  of  3:2.  This  is  owing  to  the  larynx 
of  men  being  much  larger  and  forming  a  more  acute  angle  anteriorly. 
The  different  pitch  observable  in  the  male  and  female  voice,  and  in  boys 
is  due  to  these  variations.  At  puberty  the  larynx  of  boys  is  increased  in 
size  and  changed  in  form,  and  the  voice  is  altered.  No  change,  however, 
takes  place  in  the  voice  of  eunuchs  from  whom  the  testes  have  been  re¬ 
moved  before  puberty.  The  unsteady,  bleating,  and  weak  tone  observ¬ 
able  in  the  voice  of  old  persons,  is  due  to  ossification  of  the  cartilages 
of  the  larynx,  an  altered  condition  of  the  vocal  chords,  and  loss  of 
nervous  and  muscular  power. 

That  the  voice  is  produced  in  the  larynx  may  be  readily  demonstrated 
by  making  an  opening  in  the  trachea  or  the  larynx  below  the  glottis  in 
animals ;  this  at  once  diverts  the  current  of  air  passing  from  the  lungs,  so 
as  to  completely  destroy  the  voice ;  closure  of  the  opening,  however,  by 
forcing  the  air  through  the  proper  channels,  restores  it.  If  the  opening 
is  made  above  the  glottis  in  man,  as  sometimes  occurs  in  unsuccessful 
suicidal  efforts  at  cutting  the  throat,  the  speech  is  lost  but  not  the  voice. 
Again,  by  blowing  with  the  bellows  a  current  of  air  through  the  tracheal 
end  of  the  larynx  of  a  slaughtered  animal,  vocal  sounds  can  be  produced, 
which  may  be  varied  by  changing  the  tension  of  the  chords. 

The  preceding  and  other  analogous  facts  afford  data  for  assuming  that 
the  vocal  ligaments  may  be  properly  regarded  as  the  organs  of  voice. 
In  a  quiescent  state  they  do  not  lie  parallel  to  each  other,  but  for  the 
purpose  of  respiration  the  aperture  of  the  glottis  is  widely  open  and 
somewhat  triangular  in  shape,  the  base  of  the  triangle  corresponding 
to  the  space  between  the  separated  arytenoid  cartilages;  the  relative 
position  of  the  chords,  as  well  as  their  tension,  however,  can  be  varied 
to  a  considerable  extent  through  the  mobility  of  the  thyroid  and  aryte¬ 
noid  cartilages.  When,  for  instance,  a  vocal  sound  is  made,  the  action 
commences  with  the  contraction  of  certain  intrinsic  muscles,  the  crico¬ 
thyroid,  by  which  the  vocal  chords  are  stretched  and  made  tense,  while 
they  are  brought  close  to  each  other,  and  in  a  parallel  direction,  so  as  to 
reduce  the  aperture  of  the  glottis  to  a  mere  linear  fissure,  by  the  crico- 
arytenoideus  lateralis  and  arytenoideus  aeting  upon  and  approximating 
the  arytenoid  cartilages.  The  air,  driven  by  a  forcible  expiration  through 
this  narrow  fissure,  not  only  causes  the  vocal  chords  to  vibrate,  but  is 


'28 


itself  thrown  into  vibrations,  and  thus  the  sound  required  is  produced. 
As  antagonists  to  the  muscles  named  above,  the  thyy'o-arytenoideus  re¬ 
laxes  the  vocal  chords,  and  the  crico-arytenoideus  posticus,  by  separating 
the  arytenoid  cartilages,  opens  the  glottis.  By  such  an  arrangement  as 
this  in  the  muscles  of  the  larynx,  and  the  mobility  of  the  cartilages,  it  is  sus¬ 
ceptible  of  an  infinite  number  of  changes  in  form,  and  capable  of  producing 
the  finest  modulations  in  the  voice.  The  tone,  pitch,  and  intensity  of  the  dif¬ 
ferent  vocal  sounds  vary  with  the  force  of  the  expiratory  effort,  the  con¬ 
formation  of  the  larynx,  and  the  degree  of  tension  which  is  given  to  the 
vocal  chords'.  The  greater  the  tension  of  the  latter,  the  more  frequent 
will  be  their  vibrations,  and  the  higher  the  pitch,  or  the  more  acute  the 
sound ;  while  a  less  degree  of  tension  of  the  chords  and  a  wider  opening 
of  the  glottis  will  produce  a  grave  and  deeper  note.  For  the  production 
of  the  deeper  notes  the  vocal  ligaments  are  so  much  relaxed  that  when  at 
rest  they  are  wrinkled,  but  they  become  stretched  by  the  current  of  air, 
and  thus  acquire  the  degree  of  tension  necessary  for  vibration. 

The  force  of  the  voice  in  man  depends  greatly  on  the  capacity  of  the 
lungs  and  the  volume  of  air  which  may  be  expelled  from  them  in  a  single 
expiration.  This  is  a  point  which  claims  special  attention  from  those 
who  are  compelled  to  speak  in  public ;  for  much  of  the  discomfort  which 
audiences  endure  in  listening  to  some  speakers  is  owing  to  the  fact  that 
in  place  of  the  voice  being  formed  by  a  steady  and  uninterrupted  current 
of  air  welling  up  in  expiration,  from  lungs  which  were  filled  to  their  ut¬ 
most  capacity  in  inspiration,  it  is  produced  by  the  feeble  expiration  from 
organs  but  half  inflated,  in  this  way  straining  the  vocal  apparatus  of  the 
speaker  and  trying  the  patience  of  his  auditory.  Ignorance  of  this  fact 
is  the  most  prolific  cause  of  so  many  clerical  gentlemen  suffering  from 
laryngitis,  or  clergymen's  sore-throat.  Medical  and  other  teachers  often 
speak  for  a  greater  number  of  hours  each  week,  and  yet  one  seldom  if 
ever  hears  of  their  being  afflicted  in  this  way,  and  the  same  is  true  of 
lawyers  at  the  bar,  and  the  majority  of  public  speakers. 

Such  being  the  mode  in  which  vocal  sounds  are  produced  in  the  larynx, 
the  next  step  will  be  to  consider  the  modifications  they  undergo  in  pass¬ 
ing  through  the  cavities  of  the  pharynx,  mouth,  and  nose,  by  which  they 
become  not  merely  vocal  but  articulate  sounds,  and  constitute  the  elements 
of  speech. 

The  voice,  formed  by  the  passage  of  the  air  through  the  glottis,  ac¬ 
quires  additional  force  and  intensity,  and  becomes  much  more  sonorous 
by  the  reverberations  of  the  sound  in  the  mouth  and  nasal  cavities  and 
the  sinuses  with  which  they  communicate.  When  these  cavities  are 
closed  by  coryza,  or  the  presence  of  a  polypus,  or  the  growth  of  other 
tumors,  the  voice  is  sensibly  weakened  and^  affected,  so  that  it  is  said  to 


29 


be  nasal,  though  in  truth  it  is  not,  for  it  suffers  from  want  of  the  modi¬ 
fications  which  it  should  receive  in  the  cavities  connected  with  the 
nose.  The  roof  of  the  mouth,  formed  by  the  hard  and  soft  palate, 
serves  as  a  sounding-board,  on  which  the  voice  impinges,  and  is  then 
driven  from  the  mouth.  (See  Fig.  1.)  When  the  palate  is  broad  and 
shallow,  the  teeth  regular  and  well  formed,  as  in  this  skull,  (see  figure 
at  page  24,)^  and  the  mouth  large,  there  is  nothing  to  obstruct  the 


Fig.  1. 


passage  of  the  voice,  and  under  such  circumstances  it  is  generally  clear 
and  distinct,  for  upon  the  principle  recognized  in  physics,  that  the  angle 
of  reflection  is  equal  to  the  angle  of  incidence,  the  voice,  as  it  wells 
up  from  th’e  pharynx,  constituting  the  incident  wave  of  sound,  strikes 
upon  the  palate,  and  the  reflected  wave  meeting  with  no  impediment,  is 
driven  directly  from  the  mouth.  When  the  palate  is  very  high,  narrow, 
and  angular,  and  the  teeth  irregular,  as  in  this  skull,  (Fig>2,)  the  voice, 
of  necessity,  is  materially  affected.  .For  here  again  applying  the  principles 
already  referred  to,  the  incident  wave  of  sound  impinging  upon  a  high, 
narrow,  and  angular  palate,  is  of  course  reflected,  but  in  place  of  passing 
freely  from  the  mouth  it  either  strikes  upon  the  alveolus  or  the  palatine 
surfaces  of  the  front  teeth,  and  is  then  driven  back  to  the  pharynx.  The 
resulting  sound  arising  from  this  is  of  the  most  indistinct,  mufiled,  and 
cavernous  character,  and  almost  unfits  a  person  so  constituted  from  public 


30 


speaking.  The  impediment  which  Demosthenes  is  said  to  have  conquered 
was  slight  in  comparison  with  it.  The  application  of  the  principles  just 
made  no  doubt  has  suggested  itself  to  the  minds  of  others,  but  I  have 
never  heard  it  expressed  or  met  with  it  anywhere.  It  is  advanced  for  what 
it  is  worth,  and  without  any  pretentious  claims  to  originality,  as  an  idea 
which  would  naturally  suggest  itself  to  any  thinking  mind  after  observing 
the  different  conformation  of  the  parts.  The  most  distressing  cases  to 
speakers  and  listeners  are  those  unfortunate  persons  who,  either  from 
congenital  deficiencies  or  as  the  result  of  tertiary  syphilis,  have  an  open- 


Fig.  2. 


ing  through  the  hard  and  soft  ♦palate.  Thanks,  however,  to  the  applica¬ 
tion  and  ingenuity  of  Dr.  Kingsley,  of  New  York,  this  defect  can  now 
be  readily  obviated,  and  the  speech  made  clear  and  distinct. 

Speech,  or  articulated  sound,  as  we  have  already  seen,  is  a  gift  pecu¬ 
liar  to  man,  and  is  the  result  of  education  and  imitation.  -Division  of 
these  sounds  has  been  made,  on  account  of  their  origin  and  variations, 
into  vowels  and  consonants.  They  are  accomplished  by  the  soft  and 
hard  palates, -^he  teeth,  tongue,  lips,  and  cheeks,  and  it  is  important  that 
these  should  be  in  a  perfect  condition  to  insure  distinct  articulation. 

The  vowels,  A,  E,  I,  0,  XJ,  are  continued  sounds,  which  the  voice  fur¬ 
nishes  almost  completely  formed ;  as  they  need  for  their  articulation  little 
more  than  opening  the  mouth,  at  varying  distances,  by  the  separation  of 
the  jaws  and  lips,  a  slight  elevation  or  depression  of  the  tongue  accom¬ 
panying  this  in  the  pronunciation  of  some  of  the  vowels. 

The  consonants,  as  their  name  indicates,  serve  to  unite  together  the 


31 


vowels.  Their  pronunciation,  affected  by  interruptions  to  the  passage  of 
the  air  in  some  parts  of  the  oral  cavity,  by  various  and  complicated  mo¬ 
tions  of  the  lips  and  tongue,  the  latter  of  which,  when  applied  to  the  palate 
or  teeth,  narrow  or  close  the  channel  for  its  exit,  is  always  less  natural 
and  more  difficult  than  the  vowels.  The  most  harmonious  languages, 
and  the  most  pleasing  to  the  ear,  are  those  which  use  the  fewest  conso¬ 
nants  and  the  most  vowels.  The  division  of  the  letters  of  the  alphabet 
into  vowels  and  consonants,  has  not  been  thought  sufficient;  but  the 
consonants  have  been  further  distinguished  according  to  the  parts  which 
are  more  especially  engaged  in  the  mechanism  of  their  pronunciation, 
by  the  epithets  dental,  lingual,  labial,  nasal,  and  guttural.  The  special 
consideration  of  the  exact  action  of  the  velum,  tongue,  and  lips  in  the 
pronunciation  of  the  different  vowels  and  consonants,  would  involve  more 
time  than  we  have  at  our  command  at  present ;  it  is  a  subject,  how¬ 
ever,  worthy  of  careful  study  on  the  part  of  the  dental  practitioner,  and 
intimacy  with  it  must  impress  upon  him  the  importance  and  necessity  of 
exercising  the  greatest  care  to  so  conduct  his  operations,  whether  upon 
the  natural  teeth  or  in  the  construction  of  artificial  substitutes,  as  not 
to  mar  the  speech  of  his  patient.  This  would  be  unfortunate  under  any 
circumstances,  but  when  occurring  to  one  who  is  constantly  compelled 
to  speak  or  sing  in  public,  the  importance  of  the  modification  becomes 
immeasurably  magnified.  For  while  the  improper  use  of  the  file,  the  in¬ 
excusable  loss  of  a  tooth,  or  an  imperfectly  constructed  and  badly-fitting 
operation,  may  not  entirely  unfit  an  orator,  an  actor,  or  singer,  from  the 
discharge  of  his  duties,  it  is  calculated  to  produce  a  modification  in  the 
speech  not  only  perceptible  to  the  auditory,  but  the  recognition  of  that 
fact  reacting  upon  the  mind  of  the  person,  unfits  him  for  the  fullest 
development  of  his  vocal  powers. 

In  conclusion,  it  remains  for  us  to  consider  the  teeth  in  their  relation 

to — 

Appearance. — This  section  of  the  subject  more  frequently  attracts  at¬ 
tention  and  excites  comment  on  the  part  of  ordinary  observers  than  the 
portions  already  discussed,  for  even  those  who  fail  to  recognize  the  im¬ 
portance  of  the  teeth  as  masticatory  organs,  or  who  from  physical  im¬ 
perfections  in  the  auditory  apparatus,  or  the  existence  of  mental  defects 
which  render  them  incapable  of  distinguishing  variations  in  sound,  as  a 
general  thing  at  least  readily  notice  any  deviation  from  the  ordinary  ap¬ 
pearance  of  the  teeth.  And  no  single  feature  of  the  face  is  more  capable 
of  changing  the  entire  expression  than  the  teeth.  This  is  markedly  evi¬ 
dent  when  a  classic  face,  which  in  repose  excites  admiration  on  account 
of  the  symmetry  and  regularity  of  the  features  and  the  purity  of  the  skin, 
has  not  only  the  illusion  dispelled  at  once,  but  a  feeling  of  loathing  in- 


32 


duced,  by  a  smile  revealing,  in  place  of  pearls,  blackened  and  crumbling 
snags ;  while,  on  the  other  hand,  a  very  ordinary  and  homely  face  when 
lighted  up  by  a  smile  which  uncovers  clean,  white,  regular,  and  symmetri¬ 
cal  teeth,  becomes  pleasing  and  attractive. 

It  is  said  that  the  teeth  of  Americans  are  more  frail,  and  that  the  preva¬ 
lence  of  dental  caries,  and,  as  a  consequence,  disfigured  mouths,  is  more 
common  with  us  than  with  Europeans  and  people  in  other  parts  of  the 
world.  Writers  generally,  in  and  out  of  the  dental  profession,  appear 
disposed  to  adopt  this  as  an  unquestioned  fact ;  for  my  own  part,  however, 
I  am  somewhat  inclined  to  doubt  the  accuracy  of  this  conclusion,  for  per¬ 
sons  whose  intelligence,  keen  perceptions,  and  clear  judgment  can  be  re¬ 
lied  on,  have  informed  me  that  when  traveling  through  Europe  they  have 
paid  special  attention  to  this  matter,  and  have  found  the  teeth  of  the  in¬ 
habitants  of  the  countries  through  which  they  passed  not  merely  as  bad,- 
but  a  great  deal  worse  than  Americans,  for  they  do  not  pay  that  atten¬ 
tion  to  the  preservation,  or  restoration  of  the  organs  which  is  so  universal 
with  us. 

Again,  it  is  asserted,  as  an  evidence  of  the  physical  degeneracy  of  our 
times,  that  the  teeth  of  the  present  day  are  greatly  inferior  to  those  of 
preceding  generations.  This,  however,  is  an  open  question,  as  the  opinion 
merely  rests  upon  suppositions  and  not  reliable  data.  It  is  inferred,  for 
instance,  because  hale  and  hearty  parents  and  grandparents  who  have  at¬ 
tained  to  a  green  old  age,  and  retaining  their  teeth,  in  keeping  with  the 
general  physical  conformation,  that  all,  or  a  vast  majority  of  the  teeth  of 
the  generations  to  which  they  belonged,  were  equally  as  good.  It  is 
much  more  reasonable,  however,  to  believe  that  the  same  physical  weak¬ 
ness  and  the  operation  of  external  influences  which  shortened  the  lives  of 
millions  who  were  born  at  the  same  period,  produced  the  same  effects 
upon  the  teeth  of  these  millions,  as  we  notice  in  those  of  our  own  day. 

Unfortunately  we  have  no  exact  data  to  go  upon,  so  far  as  the  univer¬ 
sality  of  dental  caries  is  concerned  in  the  past;  but  the  testimony  of 
Shakspeare,  that 

“ - there  was  never  yet  philosopher 

That  could  endure  the  toothache  patiently,” 

proves  that  it  has  prevailed  to  a  greater  or  less  extent  in  all  time.  With 
regard  to  preceding  generations  in  our  country,  we  have  the  testimony  of 
Moore,  who,  in  giving  a  description  of  a  party  with  whom  he  traveled 
through  Yirginia  in  1802,  says  of  one  of  them  : — 

“What  a  pity,  blooming  girl, 

That  lips,  so  ready  for  a  lover, 

Should  not  beneath  their  ruby  casket  cover 
One  tooth  of  pearl  I 

But,  like  a  rose  by  the  church-yard-stone, 

Be  doom  d  to  blush  o’er  many  a  mouldering  bonel” 


33 


And  then  adds  in  a  foot-note,  ‘'Polygnotus  was  the  first  painter,  says 
Pliny,  who  showed  the  teeth  in  his  portraits.  He  would  scarcely,  I  think, 
have  been  tempted  to  such  an  innovation  in  America.” 

How  much  of  this  statement  is  to  be  relied  upon  as  truthful  of  that 
period,  and  what  allowance  is  to  be  made  for  the  imagination  of  the  poet, 
and  the  disposition  to  satirize  a  people  whom  he  neither  understood  nor 
admired,  is  now  difficult  to  determine.  In  whatever  way  we  accept  the 
testimony,  it  is  at  least  evident  that  our  teeth  have  not  become  worse; 
but,  on  the  contrary,  it  is  rather  to  be  hoped  that  on  account  of  the  atten¬ 
tion  which  they  now  receive  in  contrast  to  a  former  period,  when  there 
were  few  if  any  skillful  dental  practitioners,  that  they  have  rather  im¬ 
proved  than  otherwise. 

To  whatever  extent  dental  caries  may  prevail  within  our  own  country  or 
elsewhere,  there  is  no  face,  however  beautiful  or  homely,  that  is  not  more  or 
less  affected  by  the  condition  of  the  teeth ;  to  this  end  therefore  it  is  import¬ 
ant  that  irregularities  of  the  teeth  should  be  corrected,  if  no  other  reasons 
existed  in  favor  of  such  efforts ;  and  that  every  exertion  should  be  put 
forth  to  save  the  natural  organs  when  affected  by  decay.  For  to  do  this 
is  the  highest  order  of  surgery,  and  in  all,  but  very  rare  and  exceptional 
cases,  artificial  substitutes,  however  perfectly  constructed,  fail  to  entirely 
restore  the  lost  expression.  It  is  not  enough,  however,  to  merely  save 
the  teeth,  but  the  aim  should  be  to  preserve,  so  far  as  it  is  possible,  the 
natural  form  and  size  of  the  organs,  and  to  so  conduct,  and  construct  the 
operations  as  to  make  the  least  possible  exhibition  of  them  when  the 
patient  opens  his  mouth.  However  gratifying  it  may  be  to  the  pride  of 
a  dentist  to  have  his  work  made  evident  to  all  men  in  this  way,  if  an 
operation  or  a  series  of  operations  have  been  accomplished  at  an  unneces¬ 
sary  and  unjustifiable  loss  of  the  anatomical  characteristics  of  the  teeth 
and  a  great  part  of  their  utility  as  masticatory  organs,  the  work,  however 
beautiful  to  look  upon  as  a  mere  piece  of  handicraft,  cannot  be  regarded 
as  in  the  fullest  sense  a  complete  success,  or  as  a  course  which  should  be 
commended  or  adopted  by  others.  There  are  cases  in  which  the  opera¬ 
tions,  on  account  of  the  extensive  ravages  of  decay  and  the  portion  of  the 
tooth  affected,  must  show.  To  these,  of  course,  the  remark  just  made  has 
no  reference. 

The  general  appearance  of  the  face  is  not  merely  affected  by  the  con¬ 
dition,  presence,  or  absence  of  the  front  teeth,  but  the  hollow,  sunken  cheek 
reveals  in  the  most  unmistakable  manner  the  loss  of  bicuspids  and  mo¬ 
lars.  The  symmetry  of  the  face  in  this  way  is  frequently  destroyed  by  the 
inexcusable  extraction  of  these  teeth  because  a  proper  valuation  is  not 
placed  upon  them  as  masticate ry  organs,  and  on  the  score  of  appearance, 
by  practitioners  and  patients,  it  being  supposed  that,  as  back  teeth,  their 


34 


absence  will  never  be  noticed.  As  an  illustration  of  the  effect  sometimes 
produced  by  the  adoption  of  such  a  course,  observe  this  skull,  in  which  you 
see  that  the  orbit,  the  malar,  and  superior  maxillary  bones  on  the  left  side 
are  very  much  depressed  or  lowered  in  comparison  with  the  right  side ; 
and  this,  beyond  a  question  of  doubt,  is  due  to  the  extraction  of  the  left 
inferior  molars,  and  must  have  given  a  very  singular  expression  to  the 
person  during  life.  There  are  very  few  faces,  when  examined  critically, 
in  which  both  sides  will  be  found  symmetrical,  or  in  harmony  with  each 
other.  One  side,  for  instance,  will  be  round  and  full,  and  the  other  hol¬ 
low  and  sunken;  after  making  every  allowance  for  congenital  defects, 
falls,  blows,  and  other  accidents,  in  the  majority  of  these  cases  the  vari¬ 
ation  or  deformity,  for  it  often  amounts  to  that,  has  been  caused  by  the 
loss  of  molars  and  bicuspids,  many  of  which  might  have  been  saved  if 
their  true  value  had  been  duly  appreciated. 

In  the  introduction  of  artificial  teeth,  the  greatest  care  of  course  should 
be  exercised  to  preserve  or  restore  the  natural  appearance  of  the  face.  To 
do  this  with  any  prospect  of  success,  however,  it  is  important  that  the 
anatomy  and  physiology  of  expression  should  be  made  a  careful  object  of 
study. 

It  is  important,  for  instance,  that  the  teeth  should  be  so  arranged  as 
not  to  give  a  sunken  appearance  to  the  mouth,  or  to  make  it  so  promi¬ 
nent  as  to  obliterate  the  groove  or  depression  in  the  middle  of  the  upper 
lip ;  the  concavity  which  naturally  belongs  to  the  space  between  the  lower 
lip  and  chin ;  and  the  lines  which  the  action  of  the  muscles  create  on  each 
side  of  the  mouth,  extending  from  the  wings  of  the  nose  to  the  corners  of 
the  lips. 


*  V' 


